It has been a long time since pocket corkscrew replaced professional use of traditional corkscrews, especially when they are used by operators in restaurants, hotels, communities, etc. Such pocket corkscrews were conceived as pocket knives (provided with blades and various tools) and were, therefore, handy and light, so that they can be inserted in a small pocket after using and after pivoting various tools to their rest positions. An additional advantage of pocket corkscrews is their obvious lower cost relative to traditional corkscrews.
A typical prior art pocket corkscrew comprises a cork extracting element in the form of a screw which is inserted in the cork and a propping element, which in use is leaned on the bottle neck. In their rest positions, the screw and the propping element are pivoted in such a way that they are received in the handle. When a bottle is to be uncorked, the propping element is pivoted externally, and the screw is pivoted in such a way that it can take up a substantially vertical position with respect to the handle. In that position, it is possible to screw the screw along the axis of the cork. At this point, the propping element is pivoted in such a way as to lean, with its external end, on the bottle neck. The handle, as a second class lever, is rotated around its fulcrum, which is placed on an end of the handle, with resistance substantially close to the point where force is applied. As soon as the corkscrew is activated, the handle is pivoted around the fulcrum of the propping element, which operates as a rotation fulcrum, whereby the screw is lifted and the cork is extracted from the bottle neck together with it.
The main drawback of a typical prior art pocket corkscrew lies in the fact that it is usually not possible to get a complete extraction of a cork with just one extraction operation. That is, it is usually necessary to repeat the screwing of the cork and the subsequent operation of leaning the propping element on the bottle neck, before completing the extraction operation. This is what typically happens with middle and large sizes of corks (up to 5 centimeters).
Indeed, some solutions have previously been conceived which allow a complete cork extraction from the bottle neck, avoiding a second cork screwing operation of the extraction element.
In a first known pocket corkscrew (European patent application--publication No. 0 041 026 of Feb. 2, 1981), the propping element is made of two elements (5, 6), the shorter one of which (5) is leaned on the bottle neck during a first phase of the extraction process, whereas the longer element (6) replaces the shorter element (5) in a second phase in order to complete the cork extraction process.
A second known pocket corkscrew is disclosed in U.S. Pat. No. 4,584,911, granted Apr. 9, 1989. It includes a slot provided with two notches 22, 23. A pin 13 is adapted to cooperate with one or the other of the two notches 22, 23, in either of which the pin 13 is the fulcrum of the propping element 21. The pin 13 can be manually adjusted inside the slot in order to increase the arm length between the pin 13 and the pin 15 of the extraction element 14 during the second phase of the cork extraction process. As previously stated, a manual adjustment operation is necessary in every case, which makes lost time to the operator. In addition, after extracting the cork, the pin 13 has to be replaced in its starting position.
The same U.S. patent describes a slot 26 inside which a pivot of the handle 11 runs from a first position 25 to a second position 17 of the pin 13, thanks to the action of the propping element 12 against a cam 18, which is formed on an end of the handle 11. The advantage of this solution mainly consists in the fact that the length of the arm between 25, 17 is gradually increased during passage from the first to the second phase of the cork extraction process. Beside production cost of pieces (in detail, it is necessary to provide a coating of slot 26 with a covering or metal protection clamp), the fulcrum 13 has to be returned back from 15 to 25 before arranging various tools (e.g., the extraction element and the propping element) in their rest positions, since otherwise the element 12 is not allowed to be positioned on the edge of a bottle neck for operating a further first phase of an extraction process. Therefore, the device disclosed in the U.S. patent requires both high production costs and a reloading operation before its further use.
Another pocket corkscrew was suggested in an Italian patent application, filed Jun. 1990 No. 83416-A/90, where, instead of the slot and cam of the previously mentioned device, the pin 2 around which the propping element rotates is pivotally and eccentrically mounted on a second pin 4, which is, in its turn, adapted to rotate in a seat obtained at an end of the handle 1. The propping element is adapted to acquire an initial position (so that it can cover the first extraction run). In correspondence of that position, the pin around which the propping element is pivotally mounted shapes a certain arm with a pin of the extraction element, while the pin around which the propping element is pivotally mounted acquires a position which causes the length of the arm to be substantially increased. This device can present a functional simplification of the previously described device. However, it gives rise to complications, due to the facts that:
a) if an activation of the corkscrew is required, it is necessary to open both the extraction element and the propping element in such a way that the position of the fulcrum 2' of the propping element, which is intermediate between the previously described first and second position, is reached; PA1 b) after completing a first cork extraction, it is often necessary to manually make sure that the propping element is so positioned that a second cork extraction can be completed.